The common peroneal nerve (common fibular nerve; external popliteal nerve; peroneal nerve), about one-half the size of the tibial nerve, is derived from the dorsal branches of the fourth and fifth lumbar and the first and second sacral nerves.

It descends obliquely along the lateral side of the popliteal fossa to the head of the fibula, close to the medial margin of the Biceps femoris muscle.

It lies between the tendon of the Biceps femoris and lateral head of the Gastrocnemius muscle, winds around the neck of the fibula, between the Peronæus longus and the bone, and divides beneath the muscle into the superficial peroneal nerve (superficial fibular nerve) and deep peroneal nerve (deep fibular nerve).

Trauma to the nerve can result in a condition called "foot drop," where dorsiflexion of the foot is compromised and the foot drags during walking, and sensory loss to the dorsal surface of the foot and portions of the anterior, lower-lateral leg.

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Previous to its division it gives off articular and lateral sural cutaneous nerves.

The articular branches (rami articulares) are three in number:

Two of these accompany the superior and inferior lateral genicular arteries to the knee; the upper one occasionally arises from the trunk of the sciatic nerve.

The third (recurrent) articular nerve is given off at the point of division of the common peroneal nerve; it ascends with the anterior recurrent tibial artery through the Tibialis anterior to the front of the knee.

The lateral sural cutaneous nerve (n. cutaneus suræ lateralis; lateral cutaneous branch) supplies the skin on the posterior and lateral surfaces of the leg; one branch, the peroneal anastomotic (n. communicans fibularis), arises near the head of the fibula, crosses the lateral head of the Gastrocnemius to the middle of the leg, and joins with the medial sural cutaneous to form the sural nerve. The peroneal anastomotic is occasionally continued down as a separate branch as far as the heel.

In the surgical treatment of deep peroneal n. entrapment in the foot, a ligament from the extensor digitorum brevis m. that crosses over the deep peroneal nerve, putting pressure on it and causeing pain, is released.

This article was originally based on an entry from a public domain edition of Gray's Anatomy. As such, some of the information contained herein may be outdated. Please edit the article if this is the case, and feel free to remove this notice when it is no longer relevant.